Quality of farmed salmonids with emphasis on proximate composition, yield and sensory characteristics

Salmonid aquaculture has focused for many years on enhancing the quantity of fish produced. However, optimization of the quality of salmonids may lead to improved consumer acceptance and higher prices for the farmed product. The present review evaluates how the quality of salmonids is affected by parameters such as feed type, level of dietary intake (ration) and growth. Feed composition has a major influence on the proximate composition of salmonids. In particular, whole body lipid as well as the lipid content in the edible fillet is directly related to dietary fat content, while the fatty acid composition of the fish flesh is also strongly influenced by the dietary fatty acid profile. While fish body composition appears to be largely influenced by feed composition, an increase in other parameters such as feed ration and fish size also results in enhanced adipose deposition and decreased water content in the fish body. The protein content, however, remains more or less stable. An increase in fish body lipid content is not necessarily a negative factor, depending upon the processing procedure that follows. However, an increase in body fat content is generally accompanied by a reduction in slaughter yield, owing to an increase in the weight of viscera in relation to body weight. Although salmonid flesh quality with respect to levels of proximate constituents and yield appears to be under the strong influence of feed composition and feed amount, the sensory characteristics, such as odour, flavour, texture, etc., are only governed by these factors to a small degree. Tactics for the rearing of salmonids for specific purposes should therefore take into consideration the fact that the level of proximate constituents in the whole body as well as the fillet are readily manipulated by feed composition and feeding strategies, whereas the sensory parameters are less affected by these variables.